Resin-linear organosiloxane copolymers, such as those based on phenyl silsesquioxane and polydimethylsiloxane, can be difficult to prepare due to the incompatibility of the linear polydimethysiloxane blocks with the resinous silsesquioxane blocks. Base condensation or acid/metal catalyzed reactions have been attempted to link the intrinsically incompatible linear and resinous blocks. However, considerable fractions of unreacted material may remain and redistribution of the linear siloxane segments to lower molecular weight moieties may also occur. This results in inferior mechanical properties of such copolymers and translucent to cloudy copolymer compositions, indicative for a heterogeneous material.
A need exists to provide resin-linear organopolysiloxane copolymers in a product form that is low VOC compliant, stabilizes residual silanol groups on the resin-linear organopolysiloxane copolymer to ensure shelf stability, forms clear/transparent films upon drying, and yet is easy to apply to substrates for coating applications.